Occurrence of Different Kinds of Diseases in Sesame Cultivation in Myanmar and Their Impact to Sesame Yield

Abstract

We surveyed diseases of sesame in 10 farmers’ fields at Nay Pyi Taw, Myanmar and did interviews 25 farmers for the occurrence of diseases and its impact on yield in Magway, the major sesame growing area in Myanmar. We found phyllody, charcoal rot (root and stem rot), Alternaria leaf blight, powdery mildew, and leaf curl, based on on-site symptoms and their microscopic observation in Nay Pyi Taw. The disease incidence ranged from 5% to 30% in phyllody, from 10% to 30% in charcoal rot (root and stem rot) and 10% to 40% in Alternaria blight, while leaf curl and powdery mildew were not observed abundantly. According to interviews conducted in Magway, 60% of the farmers suffered from phyllody disease symptoms, 80% from charcoal rot, 48% from Cercospora, 28% bacterial leaf spot and 24% diseases with the symptoms of leaf roll. Most farmers (84%) noticed combinations of diseases symptoms either phyllody or charcoal rot/black and stem rot or Cercospora leaf spot and/or bacterial leaf spot. Yield losses ranged from 5 to 50% by phyllody, from 10 to 75% by charcoal rot (root and stem rot), from 5 to 50% by Cercospora leaf spot, and 5% by bacterial leaf spot. Other abnormal symptoms such as discoloring of root, seedling death and leaf yellowing were also observed and the yield losses ranged from 5 to 50%.There were no significance relations between the actual yield and yield losses estimated by each disease. A half of farmers (54%) burnt the crop residues after harvest, while 45% directly buried them in their fields including plant parts infected with diseases. Although there was no difference in sesame yield between these two practices, the average yield was higher by 15% in farmers with the burnt practice. Only a few farmers applied fungicides. Potential constraints to cause yield reduction and necessary actions to increase sesame yield are discussed.